Compact optical discs (CDs) have been available for some time for recording digitally encoded audio program material such as music. More recently, compact optical discs have been used as a kind of read-only memory (ROM) for mass storage of alphanumeric data to provide computer access to the data. Previously, numerous floppy or hard magnetic discs were required to store a comparable amount of alphanumeric data. It is possible, for example, to store data for an entire set of encyclopedias on a single compact disc.
Compact discs for audio program material typically are stored in a box-like plastic container, and when it is desired to use the disc, it is removed from the container and inserted directly into an optical laser reader. When used for mass data storage, the compact disc is preferably enclosed within a cartridge to prevent the disc from being nicked or scratched during handling. In this situation the cartridge enclosing the disc is inserted into an optical reader. Such cartridges typically have a sliding door which is opened by an actuator arm after the cartridge is inserted in the optical reader.
Because of the multiplicity of relatively movable parts which comprise the cartridge, such cartridges have been relatively expensive to produce, and have experienced problems in usage, particularly with respect to opening and closing of the sliding door. It has not been uncommon for the door to become dislodged from its support track, or become disengaged or deformed, rendering the cartridge unusable.